#include <iostream>
#include <string>
using namespace std;
int main(){
    int A, B;
    cin >> A >> B;
    string S;
    cin >> S;

    bool ans = true;
    for(int i=0; i<=A+B; i++){
    if(A==i){
        if(S[i]!='-'){
            ans = false;
            break;
        }
    }else{
        if(S[i]<'0' || '9'<S[i]){
            ans = false;
            break;
        }
    }

    if(ans) cout << "Yes\n";
    else cout << "No\n";
    return 0;
}
