#include<cstdio>
#include<cstdlib>
#include<algorithm>
using namespace std;
typedef long long ll;

const int T=700;

const ll f[]={
  0LL,1LL,8LL,36LL,120LL,330LL,792LL,1716LL,3432LL,6435LL,11440LL,19448LL,31824LL,50388LL,77520LL,116280LL,170544LL,245157LL,346104LL,480700LL,657800LL,888030LL,1184040LL,1560780LL,2035800LL,2629575LL,3365856LL,4272048LL,5379616LL,6724520LL,8347680LL,10295472LL,12620256LL,15380937LL,18643560LL,22481940LL,26978328LL,32224114LL,38320568LL,45379620LL,53524680LL,62891499LL,73629072LL,85900584LL,99884400LL,115775100LL,133784560LL,154143080LL,177100560LL,202927725LL,231917400LL,264385836LL,300674088LL,341149446LL,386206920LL,436270780LL,491796152LL,553270671LL,621216192LL,696190560LL,778789440LL,869648208LL,969443904LL,1078897248LL,1198774720LL,1329890705LL,1473109704LL,1629348612LL,1799579064LL,1984829850LL,2186189400LL,2404808340LL,2641902120LL,2898753715LL,3176716400LL,3477216600LL,3801756816LL,4151918628LL,4529365776LL,4935847320LL,5373200880LL,5843355957LL,6348337336LL,6890268572LL,7471375560LL,8093990190LL,8760554088LL,9473622444LL,10235867928LL,11050084695LL,11919192480LL,12846240784LL,13834413152LL,14887031544LL,16007560800LL,17199613200LL,18466953120LL,19813501785LL,21243342120LL,22760723700LL,24370067800LL,26075972546LL,27883218168LL,29796772356LL,31821795720LL,33963647355LL,36227890512LL,38620298376LL,41146859952LL,43813786060LL,46627515440LL,49594720968LL,52722315984LL,56017460733LL,59487568920LL,63140314380LL,66983637864LL,71025753942LL,75275158024LL,79740633500LL,84431259000LL,89356415775LL,94525795200LL,99949406400LL,105637584000LL,111600996000LL,117850651776LL,124397910208LL,131254487936LL,138432467745LL,145944307080LL,153802846692LL,162021319416LL,170613359082LL,179593009560LL,188974733940LL,198773423848LL,209004408899LL,219683466288LL,230826830520LL,242451203280LL,254573763444LL,267212177232LL,280384608504LL,294109729200LL,308406729925LL,323295330680LL,338795791740LL,354928924680LL,371716103550LL,389179276200LL,407340975756LL,426224332248LL,445853084391LL,466251591520LL,487444845680LL,509458483872LL,532318800456LL,556052759712LL,580688008560LL,606252889440LL,632776453353LL,660288473064LL,688819456468LL,718400660120LL,749064102930LL,780842580024LL,813769676772LL,847879782984LL,883208107275LL,919790691600LL,957664425960LL,996867063280LL,1037437234460LL,1079414463600LL,1122839183400LL,1167752750736LL,1214197462413LL,1262216571096LL,1311854301420LL,1363155866280LL,1416167483302LL,1470936391496LL,1527510868092LL,1585940245560LL,1646274928815LL,1708566412608LL,1772867299104LL,1839231315648LL,1907713332720LL,1978369382080LL,2051256675104LL,2126433621312LL,2203959847089LL,2283896214600LL,2366304840900LL,2451249117240LL,2538793728570LL,2629004673240LL,2721949282900LL,2817696242600LL,2916315611091LL,3017878841328LL,3122458801176LL,3230129794320LL,3340967581380LL,3455049401232LL,3572453992536LL,3693261615472LL,3817554073685LL,3945414736440LL,4076928560988LL,4212182115144LL,4351263600078LL,4494262873320LL,4641271471980LL,4792382636184LL,4947691332727LL,5107294278944LL,5271289966800LL,5439778687200LL,5612862554520LL,5790645531360LL,5973233453520LL,6160734055200LL,6353256994425LL,6550913878696LL,6753818290868LL,6962085815256LL,7175834063970LL,7395182703480LL,7620253481412LL,7851170253576LL,8088059011227LL,8331047908560LL,8580267290440LL,8835849720368LL,9097930008684LL,9366645241008LL,9642134806920LL,9924540428880LL,10214006191389LL,10510678570392LL,10814706462924LL,11126241217000LL,11445436661750LL,11772449137800LL,12107437527900LL,12450563287800LL,12801990477375LL,13161885792000LL,13530418594176LL,13907760945408LL,14294087638336LL,14689576229120LL,15094407070080LL,15508763342592LL,15932831090241LL,16366799252232LL,16810859697060LL,17265207256440LL,17730039759498LL,18205558067224LL,18691966107188LL,19189470908520LL,19698282637155LL,20218614631344LL,20750683437432LL,21294708845904LL,21850913927700LL,22419525070800LL,23000772017080LL,23594887899440LL,24202109279205LL,24822676183800LL,25456832144700LL,26104824235656LL,26766903111198LL,27443323045416LL,28134341971020LL,28840221518680LL,29561227056647LL,30297627730656LL,31049696504112LL,31817710198560LL,32601949534440LL,33402699172128LL,34220247753264LL,35054887942368LL,35906916468745LL,36776634168680LL,37664346027924LL,38570361224472LL,39494993171634LL,40438559561400LL,41401382408100LL,42383788092360LL,43386107405355LL,44408675593360LL,45451832402600LL,46515922124400LL,47601293640636LL,48708300469488LL,49837300811496LL,50988657595920LL,52162738527405LL,53359916132952LL,54580567809196LL,55825075869992LL,57093827594310LL,58387215274440LL,59705636264508LL,61049493029304LL,62419193193423LL,63815149590720LL,65237780314080LL,66687508765504LL,68164763706512LL,69669979308864LL,71203595205600LL,72766056542400LL,74357814029265LL,75979323992520LL,77631048427140LL,79313455049400LL,81027017349850LL,82772214646616LL,84549532139028LL,86359460961576LL,88202498238195LL,90079147136880LL,91989916924632LL,93935323022736LL,95915887062372LL,97932136940560LL,99984606876440LL,102073837467888LL,104200375748469LL,106364775244728LL,108567596033820LL,110809404801480LL,113090774900334LL,115412286408552LL,117774526188844LL,120178087947800LL,122623572295575LL,125111586805920LL,127642746076560LL,130217671789920LL,132836992774200LL,135501345064800LL,138211371966096LL,140967724113568LL,143771059536281LL,146622043719720LL,149521349668980LL,152469657972312LL,155467656865026LL,158516042293752LL,161615517981060LL,164766795490440LL,167970594291643LL,171227641826384LL,174538673574408LL,177904433119920LL,181325672218380LL,184803150863664LL,188337637355592LL,191929908367824LL,195580749016125LL,199290952927000LL,203061322306700LL,206892668010600LL,210785809612950LL,214741575477000LL,218760802825500LL,222844337811576LL,226993035589983LL,231207760388736LL,235489385581120LL,239838793758080LL,244256876800992LL,248744535954816LL,253302681901632LL,257932234834560LL,262634124532065LL,267409290432648LL,272258681709924LL,277183257348088LL,282183986217770LL,287261847152280LL,292417829024244LL,297652930822632LL,302968161730179LL,308364541201200LL,313843099039800LL,319404875478480LL,325050921257140LL,330782297702480LL,336600076807800LL,342505341313200LL,348499184786181LL,354582711702648LL,360757037528316LL,367023288800520LL,373382603210430LL,379836129685672LL,386385028473356LL,393030471223512LL,399773641072935LL,406615732729440LL,413557952556528LL,420601518658464LL,427747660965768LL,434997621321120LL,442352653565680LL,449814023625824LL,457383009600297LL,465060901847784LL,472849003074900LL,480748628424600LL,488761105565010LL,496887774778680LL,505129989052260LL,513489114166600LL,521966528787275LL,530563624555536LL,539281806179688LL,548122491526896LL,557087111715420LL,566177111207280LL,575393947901352LL,584739093226896LL,594214032237517LL,603820263705560LL,613559300216940LL,623432668266408LL,633441908353254LL,643588575077448LL,653874237236220LL,664300477921080LL,674868894615279LL,685581099291712LL,696438718511264LL,707443393521600LL,718596780356400LL,729900549935040LL,741356388162720LL,752965996031040LL,764731089719025LL,776653400694600LL,788734675816516LL,800976677436728LL,813381183503226LL,825949987663320LL,838684899367380LL,851587743973032LL,864660362849811LL,877904613484272LL,891322369585560LL,904915521191440LL,918685974774788LL,932635653350544LL,946766496583128LL,961080460894320LL,975579519571605LL,990265662876984LL,1005140898156252LL,1020207249948744LL,1035466760097550LL,1050921487860200LL,1066573510019820LL,1082424920996760LL,1098477832960695LL,1114734375943200LL,1131196697950800LL,1147866965078496LL,1164747361623768LL,1181840090201056LL,1199147371856720LL,1216671446184480LL,1234414571441337LL,1252379024663976LL,1270567101785652LL,1288981117753560LL,1307623406646690LL,1326496321794168LL,1345602235894084LL,1364943541132808LL,1384522649304795LL,1404341991932880LL,1424404020389064LL,1444711206015792LL,1465266040247724LL,1486071034734000LL,1507128721461000LL,1528441652875600LL,1550012402008925LL,1571843562600600LL,1593937749223500LL,1616297597409000LL,1638925763772726LL,1661824926140808LL,1684997783676636LL,1708447057008120LL,1732175488355455LL,1756185841659392LL,1780480902710016LL,1805063479276032LL,1829936401234560LL,1855102520701440LL,1880564712162048LL,1906325872602624LL,1932388921642113LL,1958756801664520LL,1985432477951780LL,2012418938817144LL,2039719195739082LL,2067336283495704LL,2095273260299700LL,2123533207933800LL,2152119231886755LL,2181034461489840LL,2210282050053880LL,2239865175006800LL,2269787038031700LL,2300050865205456LL,2330659907137848LL,2361617439111216LL,2392926761220645LL,2424591198514680LL,2456614101136572LL,2488998844466056LL,2521748829261662LL,2554867481803560LL,2588358254036940LL,2622224623715928LL,2656470094548039LL,2691098196339168LL,2726112485139120LL,2761516543387680LL,2797313980061224LL,2833508430819872LL,2870103558155184LL,2907103051538400LL,2944510627569225LL,2982330030125160LL,3020565030511380LL,3059219427611160LL,3098297048036850LL,3137801746281400LL,3177737404870436LL,3218107934514888LL,3258917274264171LL,3300169391659920LL,3341868282890280LL,3384017972944752LL,3426622515769596LL,3469685994423792LL,3513212521235560LL,3557206237959440LL,3601671315933933LL,3646611956239704LL,3692032389858348LL,3737936877831720LL,3784329711421830LL,3831215212271304LL,3878597732564412LL,3926481655188664LL,3974871393896975LL,4023771393470400LL,4073186129881440LL,4123120110457920LL,4173577874047440LL,4224563991182400LL,4276083064245600LL,4328139727636416LL,4380738647937553LL,4433884524082376LL,4487582087522820LL,4541836102397880LL,4596651365702682LL,4652032707458136LL,4707984990881172LL,4764513112555560LL,4821622002603315LL,4879316624856688LL,4937601977030744LL,4996483090896528LL,5055965032454820LL,5116052902110480LL,5176751834847384LL,5238067000403952LL,5300003603449269LL,5362566883759800LL,5425762116396700LL,5489594611883720LL,5554069716385710LL,5619192811887720LL,5684969316374700LL,5751404684011800LL,5818504405325271LL,5886274007383968LL,5954719053981456LL,6023845145818720LL,6093657920687480LL,6164163053654112LL,6235366257244176LL,6307273281627552LL,6379889914804185LL,6453221982790440LL,6527275349806068LL,6602055918461784LL,6677569629947458LL,6753822464220920LL,6830820440197380LL,6908569615939464LL,6987076088847867LL,7066345995852624LL,7146385513605000LL,7227200858670000LL,7308798287719500LL,7391184097726000LL,7474364626157000LL,7558346251170000LL,7643135391808125LL,7728738508196376LL,7815162101738508LL,7902412715314536LL,7990496933478870LL,8079421382659080LL,8169192731355292LL,8259817690340216LL,8351303012859807LL,8443655494834560LL,8536881975061440LL,8630989335416448LL,8725984501057824LL,8821874440629888LL,8918666166467520LL,9016366734801280LL,9114983245963169LL,9214522844593032LL,9314992719845604LL,9416400105598200LL,9518752280659050LL,9622056568976280LL,9726320339847540LL,9831551008130280LL,9937756034452675LL,10044942925425200LL,10153119233852856LL,10262292558948048LL,10372470546544116LL,10483660889309520LL,10595871326962680LL,10709109646487472LL,10823383682349381LL,10938701316712312LL,11055070479656060LL,11172499149394440LL,11290995352494078LL,11410567164093864LL,11531222708125068LL,11652970157532120LL,11775817734494055LL,11899773710646624LL,12024846407305072LL,12151044195687584LL,12278375497139400LL,12406848783357600LL,12536472576616560LL,12667255449994080LL,12799206027598185LL,12932332984794600LL,13066645048434900LL,13202150997085336LL,13338859661256338LL,13476779923632696LL,13615920719304420LL,13756291035998280LL,13897899914310027LL,14040756447937296LL,14184869783913192LL,14330249122840560LL,14476903719126940LL,14624842881220208LL,14774075971844904LL,14924612408239248LL,15076461662392845LL,15229633261285080LL,15384136787124204LL,15539981877587112LL,15697178226059814LL,15855735581878600LL,16015663750571900LL,16176972594102840LL,16339672031112495LL,16503772037163840LL,16669282644986400LL,16836213944721600LL,17004576084168816LL,17174379269032128LL,17345633763167776LL,17518349888832320LL,17692538026931505LL,17868208617269832LL,18045372158800836LL,18224039209878072LL,18404220388506810LL,18585926372596440LL,18769167900213588LL,18953955769835944LL,19140300840606803LL,19328214032590320LL,19517706327027480LL,19708788766592784LL,19901472455651652LL,20095768560518544LL,20291688309715800LL,20489242994233200LL,20688443967788245LL,20889302647087160LL,21091830512086620LL,21296039106256200LL,21501940036841550LL,21709544975128296LL,21918865656706668LL,22129913881736856LL,22342701515215095LL,22557240487240480LL,22773542793282512LL,22991620494449376LL,23211485717756952LL,23433150656398560LL,23656627570015440LL,23881928784967968LL,24109066694607609LL,24338053759549608LL,24568902507946420LL,24801625535761880LL,25036235507046114LL,25272745154211192LL,25511167278307524LL,25751514749301000LL,25993800506350875LL,26238037558088400LL,26484238982896200LL,26732417929188400LL,26982587615691500LL,27234761331726000LL,27488952437488776LL,27745174364336208LL,28003440615068061LL,28263764764212120LL,28526160458309580LL,28790641416201192LL,29057221429314166LL,29325914361949832LL,29596734151572060LL,29869694809096440LL,30144810419180223LL,30422095140513024LL,30701563206108288LL,30983228923595520LL,31267106675513280LL,31553210919602944LL,31841556189103232LL,32132157093045504LL,32425028316549825LL,32720184621121800LL,33017640844950180LL,33317411903205240LL,33619512788337930LL,33923958570379800LL,34230764397243700LL,34539945495025256LL,34851517168305123LL,35165494800452016LL,35481893853926520LL,35800729870585680LL,36122018471988372LL,36445775359701456LL,36772016315606712LL,37100757202208560LL,37432013962942565LL,37765802622484728LL,38102139287061564LL,38441040144760968LL,38782521465843870LL,39126599603056680LL,39473290991944524LL,39822612151165272LL,40174579682804359LL,40529210272690400LL,40886520690711600LL,41246527791132960LL,41609248512914280LL,41974699880028960LL,42342899001783600LL,42713863073138400LL
};

ll K;
ll c[T+1];

int main(){
  scanf("%lld",&K);
  for (int i=T;i;i--)
    c[i]=K/f[i],K%=f[i];
  int t=T; while (!c[t]) t--;
  for (int i=t;i;i--){
    for (int j=1;j<=c[i];j++) putchar('F');
    printf("ESTIVAL");
  }
  return 0;
}


Measured memory_bytes: 128