# AOJ 0222 Prime Quadruplet
# Python3 2018.6.23 bal4u
# From Wekipedia (https://en.wikipedia.org/wiki/Prime_quadruplet)
# All prime quadruplets except {5, 7, 11, 13} are of the form
# {30n + 11, 30n + 13, 30n + 17, 30n + 19} for some integer n.

MAX = 899
diff = (0,3,3,21,22,13,7,39,7,73, \
126,119,88,3,11,66,29,17,53,42, \
101,214,104,298,252,133,255,141,76,91, \
168,81,45,56,203,301,43,66,291,223, \
92,97,442,290,437,281,38,144,549,241, \
29,192,11,518,266,490,122,130,13,329, \
85,209,71,241,290,18,301,52,120,34, \
50,805,276,217,182,53,209,155,77,468, \
448,29,90,85,91,7,146,21,309,234, \
60,213,511,59,273,364,57,77,87,231, \
452,168,154,346,273,588,11,91,322,335, \
140,221,87,442,297,95,321,498,146,182, \
8,38,11,679,111,120,83,36,59,462, \
32,349,448,333,644,63,101,960,161,759, \
255,354,270,52,200,133,112,297,298,27, \
74,577,25,182,280,584,756,266,287,277, \
119,31,561,59,179,630,34,98,1,84, \
217,234,4,48,127,528,679,35,108,15, \
752,60,31,228,559,7,35,56,43,10, \
151,374,297,294,14,60,196,133,18,63, \
63,17,35,290,953,584,66,102,427,4, \
357,507,441,420,802,14,66,171,252,88, \
14,364,32,220,66,256,427,651,52,287, \
987,214,161,319,241,1333,190,325,63,500, \
1026,60,13,112,238,144,137,349,417,32, \
164,196,115,735,200,382,273,104,119,214, \
665,235,297,665,25,34,211,280,542,375, \
188,42,134,573,350,106,17,112,676,1095, \
403,62,193,60,13,116,60,255,609,350, \
7,165,661,25,748,176,10,283,144,987, \
389,59,60,342,112,144,31,98,676,297, \
652,189,56,34,441,50,314,266,29,546, \
297,39,657,46,703,70,270,221,122,767, \
13,134,318,1222,84,650,371,92,164,760, \
318,175,158,679,496,389,273,38,676,270, \
902,228,143,196,18,287,102,409,612,1, \
56,269,311,714,1092,176,34,165,143,438, \
266,249,97,442,105,7,913,81,80,871, \
497,585,574,11,220,94,855,132,473,836, \
301,7,833,63,1145,60,1886,382,111,43, \
111,319,431,108,297,60,878,799,133,472, \
529,420,241,46,231,304,616,1145,595,447, \
589,76,399,865,154,101,119,739,528,673, \
49,994,412,1072,6,25,3,49,126,1079, \
1141,66,220,932,1049,561,692,764,476,248, \
200,1897,658,644,24,399,143,1331,839,1, \
1077,760,11,34,658,36,647,21,528,242, \
98,529,24,1117,192,396,930,224,365,66, \
557,377,757,322,203,335,770,155,97,21, \
665,484,553,321,207,116,574,272,287,253, \
637,259,38,263,62,1268,451,693,756,630, \
357,105,32,581,455,153,540,350,91,210, \
409,270,377,442,490,615,424,52,890,199, \
102,1746,462,749,24,644,540,220,840,1656, \
223,74,434,179,665,923,428,307,875,50, \
2387,276,109,363,529,550,139,798,176,150, \
297,123,66,266,414,17,130,1344,300,1799, \
8,1176,279,351,461,396,112,626,498,931, \
2782,123,1253,780,781,1119,46,39,847,468, \
1037,1144,63,332,294,1082,525,459,220,70, \
231,31,1029,256,290,662,242,98,252,13, \
1008,64,346,1211,119,802,189,272,298,122, \
697,319,195,273,410,1221,365,885,322,52, \
847,165,112,67,812,630,801,87,60,424, \
630,867,231,123,308,396,76,119,60,203, \
17,63,553,931,147,588,127,437,164,43, \
14,371,115,150,354,315,473,3,1221,245, \
36,272,214,24,385,249,182,445,171,35, \
921,300,1558,1250,129,539,476,94,11,227, \
427,151,102,126,2176,71,297,60,413,195, \
190,944,49,554,1102,676,279,78,143,364, \
357,462,1144,1050,218,423,623,364,416,239, \
143,280,248,365,77,77,1529,157,361,514, \
536,31,330,87,193,514,935,227,18,91, \
104,49,133,1149,104,518,396,1015,143,445, \
360,385,680,49,1053,669,647,931,140,231, \
31,1075,483,627,101,1012,714,346,504,60, \
917,1140,1180,98,297,1029,225,1918,406,188, \
368,466,1305,1117,1028,50,150,273,333,101, \
151,146,1100,119,1532,497,487,235,658,322, \
538,210,701,574,136,220,168,105,603,332, \
409,84,81,39,860,309,384,259,266,207, \
872,377,403,248,819,882,931,148,42,371, \
805,325,668,529,409,3151,2016,14,38,1487, \
350,295,266,343,1833,1887,123,370,260,696, \
137,962,410,132,847,1051,426,39,214,546, \
539,493,325,137,112,889,130,237,43,1183, \
118,371,1,580,316,434,2698,53,98,262, \
203,119,31,189,813,119,195,294,1435,1345, \
531,624,210,231,321,553,11,756,1358)

import bisect

tbl = [0]*MAX
for i in range(1, MAX): tbl[i] = tbl[i-1] + diff[i]
for i in range(MAX): tbl[i] = tbl[i]*30+19
while 1:
	n = int(input())
	if n == 0: break
	if n < 19: print("13")
	else:
		p = bisect.bisect_left(tbl, n)
		if tbl[p] == n: print(n)
		else: print(tbl[p-1])
