#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; i++)
using namespace std;

int main() {
    int A, B;
    string S;
    ans = "Yes\n";
    cin >> A >> B >> S;
    rep(i, A + B + 1) {
        if (i == A) {
            if (S[i] != '-') ans = "No\n";
        } else {//ハイフン以外のところ
            if (S[i] < '0' || S[i] > '9') ans = "No\n";
        }
    }
    cout << ans;
}
