int main(){
    int a, b;
    cin >> a >> b;
    string s;
    cin >> s;
    
    for (int i = 0; i < s.length(); i++) {
        if (i == a && s[i] != '-'){
            cout << "No" << endl;
            return 0;
        }
        else if (i == a && s[a] == '-')
            continue ;
        
        if ( !('0' <= s[i] && s[i] <= '9') ) {
            cout << "No" << endl;
            return 0;
        }
    }
    
    cout << "Yes" << endl;
    
    return 0;
}