When I try to enter the value of Change_In_Velocity or Time it is not taking the first digit which I am trying to feed please tell me what is the error in it.

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

#define ESC 27
#define ENTER 13

int main()
{
int formula;

start:
system("CLS");
printf("\t***SELECT FORMULA***\n");
printf("Enter Formula Number to Select Formula\n");
printf("1  = Acceleration\n");
printf("Enter Formula Number: ");
scanf("%d", &formula);

if (formula == 1)
{
while (formula)
{
float Change_In_Velocity, Time, Acceleration;
system("CLS");
printf("\tACCELERATION\n");
printf("***Enter Values In SI Units***\n\n");
printf("Change In Velocity: ");
int a;
a = getch();
switch(a)
{
case ESC:
goto start;
default:
scanf("%f", &Change_In_Velocity);
printf("Time: ");
int b;
b = getch();
switch(b)
{
case ESC:
goto start;
default:
scanf("%f", &Time);
}
}
Acceleration = Change_In_Velocity/Time;
printf("Acceleration = %f\n\n", Acceleration);

printf("Press any key to continue...\n");
printf("Press ESC to return main manu");

int c;
c = getch();
switch(c)
{
case ESC:
goto start;
default:
continue;
}
}
}
getch();
return 0;
}