#include <iostream>
#include <fstream>
#include <vector>
#include <cstring>
#include <queue>
#include <algorithm> // sort

#define REP(i, n) for (long long i = 0; i < (n); i++) 
typedef long long ll;
static const ll mod = 1000000007;
static const ll INF = 1000000000000000000LL;
                    //999999997000000003
                    //1000000000000000000

using namespace std;

int main(){
    int A,B;
    cin >> A >> B;
    string S;
    REP >> S;
    string res = "Yes";

    REP(i,S.size())
    {
        if(i == A - 1)
        {
            if(S[i] != '-')res = "No";
        }
        else
        {
            if(S[i] == '-')res = "No";            
        }
    }


    cout << res << endl;
    return 0;
}
