N,M = map(int, input().split())
A = [list(map(int, input().split())) for _ in range(N)]
A = [0]+sorted(A,key=lambda x:x[0],reverse=True)
INFTY = 10**16
F = [[0 for _ in range(M+1)] for _ in range(N+1)]
G = [[0 for _ in range(M+1)] for _ in range(N+1)]
H = [[0 for _ in range(M+1)] for _ in range(N+1)]
for j in range(1,M+1):
    if j>=A[1][1]:
        F[1][j] = A[1][0]**2
    else:
        F[1][j] = -INFTY
for i in range(2,N+1):
    for j in range(1,M+1):
        G[i][j] = max(F[i-1][j],G[i-1][j])
        H[i][j] = max(F[i-1][j]//A[i-1][0],H[i-1][j])
        if j>=A[i][1]:
            F[i][j] = H[i][j-A[i][1]]*A[i][0]+A[i][0]**2
        else:
            F[i][j] = -INFTY
print(max(F[N][M],G[N][M],0))