View Compilation Error

0_0_20923314_13843.cpp: In function 'int main()':
0_0_20923314_13843.cpp:58:61: error: second operand to the conditional operator is of type 'void', but the third operand is neither a throw-expression nor of type 'void'
         for(int i=1;i<=m;i++)scanf("%d%d",a+i,b+i),a[i]>b[i]?swap(a[i],b[i]):0,update(1,1,n-1,a[i],b[i]-1,i);
                                                             ^