2659: [Beijing wc2012]算不出的算式

数竞基础…整点…嗯

#include<cstdio>int main(){    long long p,q;    scanf("%lld%lld",&p,&q);    if(p==q)printf("%lld",((p-1)/2)*((q+1)/2));    else printf("%lld",((p-1)/2)*((q-1)/2));}