connecting_cables_DP

cables = [int(x) for x in input().split()]

positions = sorted(cables)

size = len(cables) + 1
lcs = [[0] * size for _ in range(size)]

for row in range(1, size):
    for col in range(1, size):
        if cables[row-1] == positions[col-1]:
            lcs[row][col] = lcs[row-1][col-1] + 1
        else:
            lcs[row][col] = max(lcs[row-1][col], lcs[row][col-1])

print(f'Maximum pairs connected: {lcs[size-1][size-1]}')