#include <iostream>
#include <vector>
#include <string>

using namespace std;

int main(){

int n,m;
cin>>n>>m;
int p = 1;
int q = n+1;
string sor,s;
int u;
for(int i = 0; i < m; i++){
    cin>>sor>>sor>>s>>sor>>u;
    if(s == "left"){
        if(q > u) q = u;

    }else{
        if(p <= u) p = u+1;

    }
}

if(p >= q){
    cout<<-1<<endl;
}else{
    cout<<q-p<<endl;
}

}