View Compilation Error

0_0_36247311_26999.cpp: In function 'int main()':
0_0_36247311_26999.cpp:13:39: error: 'a' was not declared in this scope
   for(int i=1;i<=m;i++) scanf("%lld",&a[i]); 
                                       ^
0_0_36247311_26999.cpp:16:21: error: 'a' was not declared in this scope
    mod[i]=(mod[i-1]+a[i])%n;
                     ^