```go
package main

import "fmt"

func main() {
	var a, b, c int
	fmt.Scan(&a, &b, &c)
	
	// We need to find minimum integer t such that:
	// b * (t + c) >= a * c
	// b * t >= c * (a - b)
	// t >= c * (a - b) / b
	
	numerator := c * (a - b)
	// Ceiling division: (numerator + denominator - 1) / denominator
	ans := (numerator + b - 1) / b
	
	fmt.Println(ans)
}
```