def main(): import sys input = sys.stdin.read().split() ptr = 0 N = int(input[ptr]) ptr += 1 v1 = 0 items = [] for i in range(1, N+1): c = int(input[ptr]) v = int(input[ptr+1]) ptr += 2 if i == 1: v1 = v else: items.append((i, c, v)) m_max = N // 2 INF = float('-inf') dp = [[INF] * (N + 1) for _ in range(m_max + 1)] dp[0][0] = 0 for (i, c, v) in items: max_t = min(c, N // i) remaining = max_t t = 1 while remaining > 0: current_t = min(t, remaining) for m in range(m_max, -1, -1): for w in range(N, -1, -1): if dp[m][w] == INF: continue new_m = m + current_t new_w = w + current_t * i if new_m > m_max or new_w > N: continue if dp[new_m][new_w] < dp[m][w] + current_t * v: dp[new_m][new_w] = dp[m][w] + current_t * v remaining -= current_t t <<= 1 max_val = [[-INF] * (N + 1) for _ in range(m_max + 1)] for m in range(m_max + 1): current_max = -INF for w in range(N + 1): if dp[m][w] > current_max: current_max = dp[m][w] max_val[m][w] = current_max for k in range(1, N + 1): ans = -INF max_m = min(k, m_max) for m in range(0, max_m + 1): remaining = k - m upper_w = N - remaining lower_w = 2 * m if upper_w < lower_w or upper_w < 0: continue if upper_w > N: upper_w = N current_val = max_val[m][upper_w] + remaining * v1 if current_val > ans: ans = current_val print(ans) if __name__ == '__main__': main()