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

int main(){
    int A,B;
    stirng S;
    cin >> A >> B >> S;
    for(int i = 0; i < A+B+1; i++) {
        if(i != A) {
            if(S[i] != '-') {
                continue;
            }
            else {
                cout << "No" << endl;
            }
        } 
        else {
            if(S[i] != '-') {
                cout << "No" << endl;
                return 0;
            }
        }
    }
    cout << "Yes" << endl;
}
