#include <iostream>
#include <string>
using namespace std;
int a,b;
string s;
int main(){
    cin>>a>>b>>s;
    for(int i=0;i<a+b+1;i++){
        if(s[i]=='-'^i==a){
            cout<<"No";
            return 0;
        }
    }
    cout<<"Yes";
}