#include <stdio.h> #include <stdlib.h> #include <string.h> #define MAX_N 1000000 #define NUM_COLORS 100 int main() { int n, i, j, found = 0; int colors[MAX_N]; int counts[NUM_COLORS] = {0}; // 输入n和n-1支画笔的颜色 scanf("%d", &n); for (i = 0; i < n - 1; i++) { scanf("%d", &colors[i]); } // 统计每种颜色的画笔数量 for (i = 0; i < n - 1; i++) { counts[colors[i]]++; } // 遍历所有可能的颜色，找出拿走的颜色 for (j = 1; j < NUM_COLORS; j++) { if (counts[j] == 1) { found = 1; break; } } // 输出结果 if (found) { printf("%d",j); } else { printf("12345"); } return 0; }