#include<iostream>
using namespace std;
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    short a, b;
    string s;
    cin >> a >> b >> s;
    if (s[a] != '-') {
        cout << "No\n";
        return 0;
    }
    for (int i = 0; i < a + b + 1; ++i) {
        if (i == a)continue;
        if (s[i] > '9' || s[i] < '0') {
            cout << "NO\n";
            return 0;
        }
    }
    cout << "Yes\n";
    return 0;
}