#include <bits/stdc++.h>

using namespace std;

int a,b,ans;
string s;

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