#include<bits/stdc++.h>
using namespace std;
int a,b,n;
int main()
{
    string s;
    cin>>a>>b;
    n=a+b;
    bool flag=false;
    cin>>s;
    if(s[a]!='-') flag=true;
    for(int i=0;i<=n;i++)
    {
        if(i==a) continue;
        if(!(s[i]>='0' && s[i]<='9')) flag=true;
    }
    if(!flag) cout<<"Yes"<<endl;
    else cout<<"No"<<endl;
    return 0;
}
