func_code_string: #include <bits/stdc++.h>   using namespace std;   int L[1220], R[1220], s[1220], pos[1220];   char ans[1220];   int main() {     int n, ok = 1, all = 0, top = 0;     scanf( %d , &n);     for (int i = 1; i <= n; ++i) {       scanf( %d%d , &L[i], &R[i]);       if (!ok) continue;       pos[i] = all;       ans[all++] =  ( ;       s[++top] = i;       while (top > 0 && pos[s[top]] + L[s[top]] <= all) {         if (pos[s[top]] + R[s[top]] >= all)           ans[all++] =  ) ;         else {           ok = 0;           break;         }         top--;       }     }     if (top > 0) ok = 0;     if (ok)       printf( %s n , ans);     else       puts( IMPOSSIBLE );     return 0;   }   