#include <iostream>
#include <fstream>
using namespace std;
ifstream f("alo.in");
ofstream g("alo.out");
int E, N, Nr, D, i, suma, prima, ultima;
int main()
{
f >> E >> N;
suma=E;
for (i=1; i<=N; ++i)
{
f >> Nr >> D;
prima=Nr/10000;
ultima=Nr%10;
if (prima==1)
{
if (ultima==9) suma+=0;
else suma=suma-2*D;
}
else
{
if (ultima==5) suma=suma+1*D;
else suma=suma;
}
}
g << suma;
}