5.21

#include<iostream>#include<vector>#include<string>using namespace std;int main(){string read, tmp;int flag = 0;while (cin >> read){if (isupper(read[0]) && read == tmp){flag = 1;break;}else tmp = read;}if (flag)cout << read << " occurs twice in succession" << endl;else cout << "no word was repeated" << endl;return 0;}