#include<bits/stdc++.h>
using namespace std;
 
int main(void){
    int a,b;cin >> a >> b;
    string s; cin >> s;

    bool isnew = false;
    int preCount = 0;
    int fuCount = 0;

    for (int i=0;i<s.size();i++){
        if (s[i]!='-'){
            if (!isnew) {
                preCount++;
            } else {
                fuCount+=;
            }
        } else {
            isnew = true;
        }
    }

    if (preCount == a && fuCount == b) {
        cout << "Yes" << endl;
        return 0;
    }

    cout << "No" << endl;
    return 0;
}