extended euclidean algorithm in c program

#include<stdio.h>
#include<conio.h>
#include<math.h>

int extended(int,int);

void main()
{
    int m,b,ans;
    clrscr();
    printf("Enter any no for which u want to find multiplicative inverse\n");
    scanf("%d%d",&m,&b);
    ans=extended(m,b);
    printf("\nThe Multiplicative Inverse Of %d is %d",b,ans);
    getch();
}
int extended(int m,int b)
{
    int a1=1,a2=0,a3=m,b1=0,b2=1,b3=b,q,t1,t2,t3;
abc:    if(b3==0)
    {
        return a3;
    }
    if(b3==1)
    {
        return b2;
    }
    q=ceil(a3/b3);
    t1=a1-(q*b1);
    t2=a2-(q*b2);
    t3=a3-(q*b3);
    a1=b1;
    a2=b2;
    a3=b3;
    b1=t1;
    b2=t2;
    b3=t3;

    goto abc;
}