#include<bits/stdc++.h>                          
using namespace std;
int a,b;
string s;
int main(){
    cin>>a>>b>>s;
    for(int i=0;i<s.size();i++)
        if((s[i]=='-'&&i!=a)||s[a]!='-') {cout<<"No";return 0;}
    cout<<"Yes";
	return 0;
}
//68871358
//76140264
//25446011
//200841159
//914174775