#include<iostream>
#include<string>
#include<ctype.h>
using namespace std;
int main()
{
    int a,b;
    cin>>a>>b;
    string s;
    cin >> s;
    int flag = 1;
    if(s[a]!='-') {flag=0; break;}
    else {
    for (int i=0; i<b; i++) {
        if(i!=a && !isdigit(s[i])) {
            flag=0; break;
        }
    }
    }
    
    cout << (flag ? "Yes" : "No") << endl;
    return 0;
}
