Codeforces Round #389 C. Santa Claus and Robot

C. Santa Claus and Robot

time limit per test

2 seconds

memory limit per test

256 megabytes

input

standard input

output

standard output

Santa Claus has Robot which lives on the infinite grid and can move along its lines. He can also, having a sequence of m points p₁, p₂, ..., p_m with integer coordinates, do the following: denote its initial location by p₀. First, the robot will move fromp₀ to p₁ along one of the shortest paths between them (please notice that since the robot moves only along the grid lines, there can be several shortest paths). Then, after it reachesp₁, it'll move top₂, again, choosing one of the shortest ways, then top₃, and so on, until he has visited all points in the given order. Some of the points in the sequence may coincide, in that case Robot will visit that point several times according to the sequence order.

While Santa was away, someone gave a sequence of points to Robot. This sequence is now lost, but Robot saved the protocol of its unit movements. Please, find the minimum possible length of the sequence.

Input

The first line of input contains the only positive integer n (1 ≤ n ≤ 2·10⁵) which equals the number of unit segments the robot traveled. The second line contains the movements protocol, which consists ofn letters, each being equal either L, or R, or U, or D. k-th letter stands for the direction which Robot traveled thek-th unit segment in: L means that it moved to the left, R — to the right,U — to the top and D — to the bottom. Have a look at the illustrations for better explanation.

Output

The only line of input should contain the minimum possible length of the sequence.

Examples

Input

4RURD

Output

2

Input

6RRULDD

Output

2

Input

26RRRULURURUULULLLDLDDRDRDLD

Output

7

Input

3RLL

Output

2

Input

4LRLR

Output

4

Note

The illustrations to the first three tests are given below.

The last example illustrates that each point in the sequence should be counted as many times as it is presented in the sequence.

题意：

题目很有意思，记录下。

已知圣诞老人送了ｘ个礼物，且老人走向每个礼物的路径都是最短路径。

现在只知道送礼物的路径，求礼物的最小数量可以是多少。

思路：

开始的时候想复杂了。

其实只要对出现过的点做标记，找到一对相反的点就能判断出有一个礼物。

之后要把之前的标记清空。

注意答案要加一，因为最后一个点一定是存在礼物的。

代码：

#include <cstdio>#include <iostream>#include <algorithm>#include <cstring>using namespace std;const int maxn = 200005;char data[maxn];int flag[5];int main(){int n;scanf("%d",&n);int i,j;scanf("%s",data+1);int ans =0;for(i=1;i<=n;i++){if(data[i]=='D'){if(flag[2]==1){ans++;memset(flag,0,sizeof(flag));}flag[1]=1;}else if(data[i]=='U'){if(flag[1]==1){ans++;memset(flag,0,sizeof(flag));}flag[2]=1;}else if(data[i]=='R'){if(flag[4]==1){ans++;memset(flag,0,sizeof(flag));}flag[3]=1;}else{if(flag[3]==1){ans++;memset(flag,0,sizeof(flag));}flag[4]=1;}}printf("%d\n",ans+1);return 0;}