F

#include <iostream>
#include <cmath>
#include <vector>
#include <queue>
#include <algorithm>
#include <string>
#include <stack>
#include <set>
#include <map>
#define pii pair <int,int>
using namespace std;
using ll = long long;
using ld = long double;
void cv(vector <int> &v){
    for (auto x: v) cout<<x<<' ';
    cout<<"\n";
}

void cvl(vector <ll> &v){
    for (auto x: v) cout<<x<<' ';
    cout<<"\n";
}


void cvv(vector <vector <int> > &v){
    for (auto x: v) cv(x);
    cout<<"\n";
}

void cc(vector <char> v){
    for (char x: v) cout<<x;
    cout<<"\n\n";
}

void cb(vector <bool> v){
    for (bool x: v) cout<<x;
    cout<<"\n\n";
}

int main()
{
    ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int n,m; cin>>n>>m;
	vector <bool> chk(m, 0), gn(m, 0);
	int couch=0, bad=0;
	for (int i = 0; i < n;++i){
        char act; cin>>act;
        vector <bool> now(n);
        for (int j =0;j<m;++j){
            char x; cin>>x;
            if (x == '0') now[j] = 0;
            else now[j] = 1;
            //cin>>now[j];
        }



        if (act == '+'){
            //continue;
            for (int j = 0;j<m;++j){
                if (now[j]){
                    //if (chk[j])
                        gn[j] = 1;
                }
            }
        }
        else{
            bool ok = 1;
            //couch++;
            //continue;
            for (int j = 0 ; j < m;++j){
                if (now[j]){
                    if (!gn[j]){
                        ok = 0;
                    }
                    gn[j] = 0;
                }
            }
            if (!ok){
                bad++;
            }
        }
        //cout<<"now\n";
        //cc(now);
        //cout<<"chk\n";
        //cb(chk);


	}
	cout<<bad<<"\n";
}
/*
4 3
+ 111
- 101
+ 001
- 111
*/