View Compilation Error

0_0_16699654_19790.cpp:9:1: error: '_int64' does not name a type
 _int64 sum[N] ;    //sum[i]表示以i为根节点的所有可能的子树大小之和
 ^
0_0_16699654_19790.cpp:10:1: error: '_int64' does not name a type
 _int64 num[N] ;    //num[i]表示以i为根节点的子树的方案
 ^
0_0_16699654_19790.cpp:14:1: error: '_int64' does not name a type
 _int64 ans ; 
 ^
0_0_16699654_19790.cpp: In function 'void dfs(int, int)':
0_0_16699654_19790.cpp:28:5: error: 'sum' was not declared in this scope
     sum[x] = 1 ;
     ^
0_0_16699654_19790.cpp:29:2: error: 'num' was not declared in this scope
  num[x] = 1 ; 
  ^
0_0_16699654_19790.cpp:40:3: error: 'ans' was not declared in this scope
   ans = (ans + sum[x]) % Z;  
   ^
0_0_16699654_19790.cpp: In function 'int main()':
0_0_16699654_19790.cpp:57:5: error: 'ans' was not declared in this scope
     ans = 0 ; 
     ^