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

int main(void){
    int a,b,check = 0;
    cin >> a >> b;
    string s;
    cin >> s;
    for(int i = 0;i < (a+b+1);i++){
        if((i != a && s[i] == '-') || (i == a && s[i] != '-'))++check;
    }
    if(check == 0)cout << "Yes";
    else cout << "No";
}