#include<stdio.h>
int main()
{
        freopen("lapte.in","rt",stdin);
        freopen("lapte.out","wt",stdout);
        scanf("%d",&N,&L);
        for(i=1;i<=n;i++)scanf("%d%d",&a[i],&b[i]);
        tinf=0;tsup=101;
        while(tsup-tinf>1)
        { tmed=(tinf+tsup)/2;
          atot=0;
          for(i=1;i<=n;i++)
           { ca[i]=tmed/a[i];atot+=ca[i];
             cb[i]=(tmed-ca[i]*a[i])/b[i];btot+=cb[i];}
          if(atot<L){tinf=tmed;continue;}
          while(atot>=L&&btot<L)
          { for(i=1;i<=N;i++)
            { //cauta i pentru care avem
              //cantitate minima de lapte a pierduta
              //pentru a castiga cel putin 1 lapte b
              
          
        }
        printf("%d",