View Compilation Error

0_0_18780419_17755.cpp: In function 'int main()':
0_0_18780419_17755.cpp:5:26: error: expected ')' before ';' token
 while(scanf("%d%d",&a,&b);scanf("%d%d",&c,&d);)
                          ^
0_0_18780419_17755.cpp:5:47: error: expected primary-expression before ')' token
 while(scanf("%d%d",&a,&b);scanf("%d%d",&c,&d);)
                                               ^