#include <iostream>
#include <fstream>
#define nmax 105
using namespace std;
int v[nmax],v2[nmax],n,L;
int solve (int t)
    {
    int dp[nmax][nmax],i,s,s1,l,j;
    for (i=1;i<=n;i++)
        for (j=t;j>=0;j--)
            {
            s=j/v[i];
            s1=(t-s*v[i])/v2[i];
            dp[i][s][s1]=1;
            }
    for (l=1;l<=n;l++)
        for (i=L;i>=1;i--)
            for (j=L;j>=1;j--)
                for ()
                    if (d[i][j]==1) dp[i+pi][j+pj]=1;
    if (dp[L][L]==1) return 1;
    return 0;
    }
int i,j,st,mid,dr,sol,;
int main()
{
    ifstream f ("lapte.in");
    ofstream g ("lapte.out");
    f>>n>>L;
    for (i=1;i<=n;i++)
        {
        f>>v[i]>>v2[i];
        }
    st=1;
    dr=20000;
    while (st<=dr)
        {
        mid=(st+dr)/2;
        if (solve(mid))
            {
            sol=mid;
            dr=mid-1;
            }
        else
            {
            st=mid+1;
            }
        }
    g<<sol;
}