https://atcoder.jp/contests/pakencamp-2019-day3/tasks/pakencamp_2019_day3_a
解説
https://atcoder.jp/contests/pakencamp-2019-day3/submissions/9144056
よーくみるとB-A+1日が答え。
int A, B; //--------------------------------------------------------------------------------------------------- void _main() { cin >> A >> B; int ans = B - A + 1; cout << ans << endl; }