import sys def main(): input = sys.stdin.read().split() ptr = 0 N = int(input[ptr]) ptr += 1 c = [] v = [] for _ in range(N): ci = int(input[ptr]) vi = int(input[ptr+1]) c.append(ci) v.append(vi) ptr += 2 INF = -10**18 dp = [[INF] * (N + 1) for _ in range(N + 1)] dp[0][0] = 0 for i in range(N): weight = i + 1 value = v[i] max_count = c[i] m = 1 remaining = max_count while remaining > 0: cnt = min(m, remaining) remaining -= cnt for k_prev in range(N, -1, -1): for w_prev in range(N, -1, -1): if dp[k_prev][w_prev] == INF: continue new_k = k_prev + cnt new_w = w_prev + cnt * weight if new_k > N or new_w > N: continue if dp[new_k][new_w] < dp[k_prev][w_prev] + cnt * value: dp[new_k][new_w] = dp[k_prev][w_prev] + cnt * value m *= 2 for k in range(1, N + 1): max_val = INF for w in range(k, N + 1): if dp[k][w] > max_val: max_val = dp[k][w] print(max_val) if __name__ == "__main__": main()