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

int main()
{
    int a, b;
    cin>>a>>b;
    string s;
    cin>>s;
    if(s[a] != '-')
    {
        cout<<"No\n";
        return 0;
    }
    for(int i = 0; i < (int)s.length(); i++)
    {
        if(i == a)
            continue;
        if(c > '9' || c < '0')
        {
            cout<<"No\n";
            return 0;
        }
    }
    cout<<"Yes\n";
    return 0;
}
