#include <fstream>

using namespace std;

ifstream fin("alo.in");
ofstream fout("alo.out");

int main()
{
    int n, e, i, nr, d;
    fin>>e>>n;
    for(i=1; i<=n; i++)
    {
        fin>>nr>>d;
        if(nr%10==5)
        {
            if(nr/10000==1)
                e=e-2*d;
            else
                e=e+d;
        }
        //fout<<e<<"\n";
    }
    fout<<e<<"\n";
    fin.close();
    fout.close();
    return 0;
}