#include <bits/stdc++.h>
using namespace std;

int main(void) {
    int a,b;
    cin >> a >> b;
    string s;
    cin >> s;
    for (int i = 0; i < s.size; i++) {
        if (s[i] == '-') {
            if (i == a+1) continue;
            cout << "No" << endl;
            return 0;
        }
    }
    cout << "Yes" << endl;
    return 0;
}
