def toRoman(i):
   a = {"M":1000,"D":500,"C":100,"L":50,"X":10,"V":5,"I":1,"IX":9,"XL":40,"CD":400,"CM":900,"XC":90,"IV":4}
   b = ["M","CM","D","CD","C","XC","L","XL","X","IX","V","IV","I"]
   idx = 0
   s = ""
   while i>0:
     while (i-a[b[idx]])>=0:
        s=s+b[idx]
        i=i-int(a[b[idx]])
     d=a[b[idx]]
     if i==0: 
       break
     idx=idx+1
   s=s.replace("LXL","XC")
   return s

print(toRoman(1978))
print(toRoman(2000))
print(toRoman(2012))