C++(씨쁠쁠)(cplusplus)-백준(baekjoon)(BaekJoon)코딩 2163번:초콜릿 자르기 답

#include <iostream>
using namespace std;
int main() {
    int N, M;
    cin >> N >> M;
    cout << (N-1) + N*(M - 1);
}